I’ll assume the typical leftist political context of it’s use implying an ‘aspirational’ view of my fellow humans they would often fall short of due to material concerns. That’s not the typical leftist political context? In a leftist political context idealism posits that ideas are the driving force of history, as if thought creates reality rather than reflecting it. This flips the actual relationship: material conditions shape consciousness, not the other way around. When we start from abstractions instead of concrete social practice, we end up justifying the status quo or chasing illusions. Real change comes from engaging with the world as it is, not as we wish it to be.